Thousands of labourers backed by water-carrying helicopters were battling to control fires that have killed two people in India's northern Himalayan state of Uttarakhand, officials said Sunday.

Fires have swept through more than 1,900 hectares (4,700 acres) of forest but have so far not threatened towns in Uttarakhand which draws tens of thousands of tourists every year, officials and media reports said.

Environment and Forests Minister Prakash Javadekar said some 6,000 labourers were being deployed to help fight the fires. They started about one month ago but according to other officials have intensified in recent days.

Javadekar told reporters the fires have broken out at 1,200 locations in the densely forested state, known for its remote valleys, over the last month.

"This can be compared with the worst fire of 2012 when fire took place in 1,300 places and (covered) more than 2,000 hectares," the minister said.

Senior Uttarakhand disaster management official Piyoosh Rautela said two people have been killed in recent days, although local media reported six deaths since the state's fire season started at the beginning of February.

He said disaster relief experts were being deployed to help those already on the ground.

"They are all working with two Indian Air Force choppers which are spraying water over isolated forest areas in the state," Rautela, executive director of Uttarakhand's disaster management and mitigation centre, told AFP.

"The forests are spread across our six districts but are all isolated and we are getting them under control," he added.

Uttarkhand, with its Himalayan mountains, rivers, treks and Hindu religious sites, is a popular destination for local tourists who flock there to escape India's harsh summer.

Officials said it was unclear what started the fires but some have linked the intensity of the blazes to the drought gripping India.

India is suffering its worst water crisis in years, with the government saying that about 330 million people, or a quarter of the population, are suffering from drought after the last two monsoons failed.